I am on a Mac and would like to steer you AWAY from iPhoto completely unless you absolutely plan to go to Aperture. Unlike other programs, iPhoto has a nasty habit of copying all of your pictures into a very unfriendly "package" where it is difficult to retrieve them for use in any other program. yes, it does some things well and is easy, but be aware of this if you're going down this path. (BTW I'm happy to hear about the upgrade path from iPhoto to Aperture, but my brother could not get this to work for some reason due to the size of his iPhoto library - go figure - so the upgrade doesn't always work it seems.)

I would suggest another alternative for very basic stuff to experiment - Google's Picasa (free with a gmail account), which is non-destructive and can operate on your photos anywhere on the computer. it also contains a very nice upload capability to their online web albums. I suggest this if you're looking for a fairly basic editing capability (color, contrast, crop, some fun filters, etc) similar to iPhoto.

Neither of these will do a lot with RAWs vs. better tools, IMHO.

I am a huge fan of Lightroom. Terrific catalog and key wording capability, excellent post-processing. Non-destructive editing. Unless you're really looking to do photo editing (as in add/delete objects, layers, or other more advanced techniques), there's no way you need photoshop over Lightroom. The learning curve on Lightroom is significant, but there are excellent online resources. The learning curve for Photoshop is crazy steep, even life-long relatively speaking.